OKLAHOMA CITY  Tornadoes sweeping across the Midwest and Plains left five people dead and several others injured in Oklahoma and damaged houses, a hospital, a jail, an Air Force base and other buildings during a weekend outburst of severe weather, authorities said.

Oklahoma emergency officials said five people died before dawn Sunday after a tornado hit in and around the northwest Oklahoma town of Woodward, the high winds damaging homes, toppling trees and downing power lines in that area about 140 miles northwest of Oklahoma City. The brunt of the damage was reported on the west side of the town of about 12,000, and in the neighboring community of Tangier.

Storms also were reported in Kansas, Iowa and Nebraska as a severe storm system raked its way across the nation’s midsection Saturday and Sunday. Lightning, large hail and heavy downpours accompanied the system.

Oklahoma Department of Emergency Management spokeswoman Keli Cain said the state medical examiner’s office confirmed five fatalities in the Woodward area early Sunday but search and rescue operations were still going on hours after the tornado hit shortly after midnight. She didn’t know the gender or age of the victims or details of their deaths but several homes were damaged.

“Significant damage and injuries have been reported,” she said in a statement.

She had no immediate count of the injured or severity of injuries. Police said search and rescue units from neighboring communities were joining in the effort. Cain said authorities were anxiously awaiting daybreak Sunday to accelerate efforts to aid the injured and take stock of the damage.

National Weather Service forecasters had issued serious outlooks that the worst of the weather in the Midwest and Plains would hit in the nighttime hours, predicting that conditions were right for exceptionally strong tornadoes. Weather officials and emergency management officials had worried most about what would happen if strong storms hit when people were sleeping, not paying attention to weather reports and unlikely to hear warning sirens.

The National Weather Service said the deadly tornado hit Woodward at 12:18 a.m. Sunday.

Woodward Mayor Roscoe Hill said warning sirens sounded loudly on Saturday afternoon when advance storms rumbled through but he didn’t hear the sirens go off for Sunday’s tornado. He said the tornado struck a mixed area of residences and businesses and there were reports of possible damage to a mobile home park.

In Kansas, a reported tornado in Wichita caused damage at McConnell Air Force Base and the Spirit AeroSystems and Boeing plants. A mobile home park was heavily damaged in the city, although no injuries or deaths were reported.

Iowa emergency officials said a large part of the town of Thurman in the western part of the state was destroyed Saturday night, possibly by a tornado, but no one was injured or killed. Fremont County Emergency Management Director Mike Crecelius said about 75 percent of the 250-person town was destroyed. Some residents took refuge at the City Hall.

A hospital in Creston, about 75 miles southwest of Des Moines, suffered roof damage and had some of its windows blown out by the storm, but patients and staff were not hurt. Medical center officials were calling other area hospitals to determine how many beds they had available in case they needed to move patients.

In Nebraska, baseball-sized hail shattered windows and tore siding from houses in and around Petersburg, about 140 miles northwest of Omaha. In southeast Nebraska, an apparent tornado took down barns, large trees and some small rural structures. Johnson County emergency director Clint Strayhorn said he was trying to determine the twister’s duration and the damage it caused.

At least 10 tornadoes were reported in Kansas, mostly in rural parts of the western and central sections of the state. A suspected tornado narrowly avoided Salina, meteorologists said. Another was on the ground for about a half-hour north of Dodge City.

Sedgwick County, home to Wichita, declared a state of disaster and said preliminary estimates suggest damages could be as high as $283 million.

Warnings for more serious storms continued. Bill Bunting, chief of operations at the Storm Prediction Center, said severe weather is possible Sunday “from east Texas and Arkansas and up into the Great Lakes.”

“The threat isn’t over with tonight, unfortunately,” he said Saturday.